The present invention relates to valves, and in particular, but not exclusively, to valves for controlling, charging, discharging and/or regulating the flow of powders and/or fluids.
Valves, such as split butterfly valves, are available in many designs and used widely for processes where product containment is required to prevent product exposure to environment and personnel working in close proximity of the product. The split valves are designed pre-dominantly for handling and contained transfer of solid state powders and granular material alike.
Split valve design allows the valve to be split open into two halves, commonly called alpha and beta halves, or active and passive halves. The valve design is such that when split, the two halves keep the contents on either side sealed and contained.
Similar to the split butterfly valve, a split ball valve can also be used for contained transfer of solids and more commonly liquids. Historically, these valves have mainly been used in pharmaceutical and biotech industries for non-sterile operations.
In sterile equipment design, full systems need to be sterilised and once sterilised, it is important to ensure sterility is maintained throughout the processing cycle, for example, adding of materials, discharging of materials, any process transfers between systems etc.
Split valves can be sterilised via a number of known methods, which include autoclaving, passing steam through the open valve, or passing other gases, such as vapourised hydrogen peroxide, through them prior to any product coming in contact with the internal surfaces or product contact parts.
Unfortunately, when one of these conventional known valves is split, sterility is lost or compromised as some of the critical surfaces of the valve and seats, when split into two halves, become exposed to the outside surrounding non-sterile atmosphere. If the split valve is subsequently re-docked, and opened up for transfer of material, the entire system can lose sterility and result in product contamination.
In the manufacture of pharmaceuticals, chemicals or biological material, effective containment is essential for the safe and hygienic handling of such compounds and materials. At each stage of the manufacturing process, handling must be controlled and managed to provide optimum protection for the operator and for maintaining the integrity of the product.
The material being handled is often hazardous to health, owing to the increasing potency of many new active pharmaceutical ingredients (APIs). Pharmaceutical and bio-manufacturing products are often manufactured under strict controls against product contamination. This is because the products are often for human consumption and the industries are heavily regulated by bodies like the FDA (Food and Drug Administration) in the United States and the MHRA (Medicines and Healthcare products Regulatory Agency) in the United Kingdom. Furthermore, the APIs may, in sufficient quantities, be hazardous to the health of an operator. It is therefore necessary to avoid direct contact between an operator and the potentially hazardous material.
To avoid such direct contact, there is an increasing requirement to mount containment enclosures around process equipment. However, the design of such enclosures must minimise any hindrance to the operation of the equipment. When using a split valve assembly, this can become difficult for an operator to handle in such contained environments.
In addition, at the conclusion of each processing operation, the interior surfaces of the structure enclosing the processing zone must be thoroughly cleaned by the operator prior to a further processing operation to minimise the risk of cross-contamination. Consequently, the pharmaceutical manufacturing industry demands good containment performance to achieve acceptable operator exposure levels.
For handling a solid (e.g. powder) or liquid product of a sensitive or hazardous (e.g. toxic) nature in a processing zone, there are available a number of different types of containment assembly. One such conventional containment assembly is a barrier isolator with gloved access to the processing zone in which a product and/or handling equipment may be manipulated. A barrier isolator may offer two fold protection, namely the use of glove ports to maintain a physical barrier between the product and the operator and an extraction fan system to create an air flow for removing airborne particles from the processing zone and capturing the particles by means of filters. In this manner, a barrier isolator can achieve high containment typically down to nanogram level.
However, isolators designed for containment and sterility combined together, maintaining a sterile and sealed environment, both for the integrity of the material being handled and an operator's health, can be very expensive.
It is an object of the present invention to overcome or alleviate one or more of the problems associated with the prior art.
In accordance with the present invention, there is provided a split valve assembly comprising two valve portions complementarily shaped such that the first can sealingly engage with and co-operate with the second to allow the movement of material therethrough, each valve portion comprising a housing, a valve seat and a valve closure member moveable between a first position in which the valve closure member is displaced from the valve seat and the valve is open, and a second position in which the valve closure member co-operates with the valve seat and the valve is closed, wherein the assembly has a first configuration in which the first and second valve portions engage with one another, the valve closure members being closed, and the valve closure members being disposed a distance apart defining, with the housing, a chamber therebetween, which is capable of being sealed from the surrounding environment, having an inlet and an outlet through which sterilising medium may pass, and a second configuration in which the valve closure members engage with one another and are movable from their first to their second position, and a third configuration in which the two valve portions are disengaged from one another.
In the third configuration the two valve portions are undocked, in the first configuration the two valve portions are partly docked and in the second configuration the two valve portions are completely docked.
The valve of the present invention is able to operate in a complete sterile manner, by use of an ‘in situ’ sterilisation step applied before completion of each docking (i.e. when in said first configuration), regardless of how many times the valve is split open and re-docked, i.e. engaged and disengaged, ensuring sterile conditions on product or material contact surfaces.
The present invention allows the valve to have a capability to have an intermediate stage, a first configuration, during docking that allows a chamber which can be isolated from the surrounding environment to be formed between the surfaces which have been exposed to the atmosphere and which are not sterilised. These surfaces need to be sterilised before they can become exposed to the internal sterile parts of the assembly and material which may pass therethrough when the valve is fully docked and open so as to prevent contamination.
The present invention allows sterilisation to be maintained throughout the process of several product or material transfers, and is capable of allowing several dockings and un-dockings (engagement and disengagement), without compromising the sterility of the material to be transferred or internal process equipment upon which the valve portions of the present invention may be mounted. The chamber may also he cleaned using fluid gases or fluids before and after the sterilisation step, or in any sequence during the engagement/disengagement cycle, enabling the valve to be aseptic and under class A conditions without the need for sterile isolators or aseptic external environments.
Each valve portion of the assembly may be mountable on a vessel for containing material, conveyance means, such as a hose, for conveying material and/or other process equipment known to the art. The means for mounting the valve portions may comprise any means known to the art, such as for example a screw thread, interference fit, bayonet attachment etc. In an alternative embodiment, the valve portions may be integrally formed with a vessel or conveyance means.
The inlet and outlet of the chamber may be closed once the movement from the first to the second configuration is complete. In so doing, the assembly ensures that the material being transferred therethrough is not contaminated with sterilising medium.
The valve seat and valve closure member are preferably complementarily shaped to ensure that a seal is formed when the valve closure member is closed.
The valve assembly may be a split butterfly valve, split ball valve, any other split valve or quick release coupling known to the art. Preferably, the assembly is a split butterfly valve.
The inlet and/or outlet of the chamber may be formed in the housing of one of the valve portions. Preferably, both the inlet and the outlet is formed in the housing of one of the valve portions.
Preferably, the valve portions form a mating pair, one being a male valve portion, the other female. The inlet and/or outlet may be formed in the housing of one or both of the valve portions. More preferably, the inlet and outlet for the chamber is formed in the female valve portion.
In one embodiment, the chamber has circular cross section. Preferably, the inlets and/or outlets are tangentially disposed with respect to the circumference of the chamber which is formed by the first and second valve portions. This facilitates a greater sterilising effect by the sterilising medium owing to the formation of a vortex induced by the movement of the sterilising medium around the chamber.
The valve assembly may comprise a plurality of inlets and outlets through which sterilising medium may pass. Preferably, the number of inlets corresponds directly to the number of outlets. More preferably, the assembly comprises two inlets and two outlets. The two inlets and outlets are preferably arranged into pairs comprising one inlet and one outlet. Where the chamber has a circular cross section, the inlets are preferably disposed diametrically opposite one another about the circumference of the chamber; and the outlets are preferably disposed diametrically opposite one another about the circumference of the chamber. This is to help promote the formation of a vortex when sterilising medium is passed through the chamber to enhance the cleaning/sterilising effect.
The valve closure member may be pivotally mounted within the valve housing by means of opposed spindles projecting from the closure member and located in corresponding recesses within the valve housing. The valve housing may be provided with a valve seat and the valve closure member can be pivotable into and out of engagement with the valve seat to close and open the valve respectively. Preferably, the spindles are integrally formed with the valve closure member. Advantageously, the spindles and the valve closure member, may be machined from a single piece of material.
Preferably, the valve seat comprises a seal member. The seal member may preferably comprise an abutment portion and a resiliently deformable portion, such as a O-ring, located between the abutment portion and the valve housing.
In an alternative embodiment, the valve closure member may be provided with a recess for receipt of a seal which, in use, is adapted to engage against a solid portion of the valve housing.
In the case where the seal is located in a recess in the valve closure member the valve closure member may further comprise an elastomeric material covering the valve closure member and the seal located thereon.
In one embodiment, the valve closure member being pivotable beyond the position in which further displacement is normally prevented by engagement with the valve seal, the valve may further comprise biassing means for biassing the valve closure member into a position beyond its normal closed position, whereby in the absence of the valve seal the valve closure member will engage the valve seat.
The valve seal may be located either on the valve housing or on the valve closure member.
In order to ensure that the chamber, defined by the housing of one or both of the first and second valve portions and the valve closure members, is capable of being sealed from the surrounding environment, an O ring and/or inflatable seal may be disposed on the housing of one or both of the valve portions. This ensures that during cleaning, whereby sterilising medium is passed through the chamber when the assembly is in its first configuration and when material is transferred through the valve there is a significantly reduced possibility of cross-contamination between the chamber and the surrounding environment, thus ensuring that the material transferred is not contaminated and maintaining operator safety.
The sterilising medium suitable for use with the assembly of the present invention may comprise a fluid, vapour and/or gas. Preferably, the medium is vaporised hydrogen peroxide, filtered nitrogen, filtered air and/or water. For materials sensitive to heat, vaporised hydrogen peroxide is preferably used, whilst for materials not generally heat sensitive, steam under pressure at temperatures ranging between 125-135° C. can be used. Pressurised and filtered air and/or nitrogen or other such gases may be used as a cleaning medium to blow any debris, particles, residues, impurities etc. out of the chamber in lieu of or in combination with other sterilising media. If it is to be used as a sterilising medium, then the aim is preferably filtered to remove potential contaminants.
The outlet may be connected to filter means and/or a catalyst to treat any waste stream from the chamber. Preferably, when vapourised hydrogen peroxide is used, the outlet is connected to a catalyst to treat the waste stream.
During use, the assembly may be switched from the first to the second configuration to allow material to be transferred therethrough. Once the material has been transferred, the assembly is switched back to the first configuration and the surfaces which are to he exposed to the surrounding environment cleaned before disengaging the two valve portions so as to prevent the operator from being exposed to any residual material left on the exposable surfaces, and thus ensuring operator safety.
In accordance with a further aspect of the present invention, there is provided a method of moving a material from one vessel to another without exposing the material to the surrounding environment comprising the use of a valve assembly as described hereinabove, the method comprising the steps of:                a) Engaging the valve portions such that the assembly conforms to its first configuration;        b) optionally cleaning the chamber;        c) sterilising the chamber;        d) displacing the valve portions such that the assembly conforms to its second configuration; and        e) opening the valve to allow the movement of material therethrough.        
Once the requisite quantity of material has been transferred, the method may also comprise the subsequent steps of:                f) displacing the valve portions such that the assembly conforms to its first configuration;        g) optionally cleaning the chamber;        h) optionally sterilising the chamber; and        i) disengaging the valve portions.        
In accordance with a further aspect of the present invention, there is provided a coupling assembly comprising two coupling portions complementarily shaped such that the first can sealingly engage with and co-operate with the second to allow the movement of material therethrough, each coupling portion comprising a housing, a coupling seat and a coupling closure member moveable between a first position in which the coupling closure member is displaced from the coupling seat and the coupling is open, and a second position in which the coupling closure member co-operates with the coupling seat and the coupling is closed, wherein the assembly has a first configuration in which the first and second coupling portions engage with one another, the coupling closure members being closed, and the coupling closure members being disposed a distance apart defining, with the housing, a chamber therebetween, which is capable of being sealed from the surrounding environment, having an inlet and an outlet through which sterilising medium may pass, and a second configuration in which the coupling closure members engage with one another and are movable from their first to their second position, and a third configuration in which the two valve portions are disengaged from one another.
Referring firstly to FIGS. 1 to 4, the valve assembly 10 comprises two valve portions, an upper and lower valve portion 12,14, each having a valve housing indicated generally at 16, 18 which are generally annular and a valve closure member 20, 20′ which is pivotally mounted within the housing. Valve housing 18 has an annular recess 19. The valve closure member 20,20′ is in the form of an annular disc and is provided with spindles 22,22′ by means of which the valve closure member is pivotally mounted within the housing. The valve closure member 20,20′ and the spindles 22,22′ are machined from a single piece of metal.